1. Field of the Invention
The present invention relates to a focus adjusting system, more specifically to a camera having a focus adjusting system which detects an in-focus state while moving a focusing lens group.
2. Description of the Prior Art
Conventional contrast detection (contrast measurement) focus adjusting systems detect a focus state while moving a focusing lens group from the near extremity to the far extremity thereof, or vice versa. Namely, conventional contrast detection focus adjusting systems detect an in-focus position where a peak contrast is obtained by performing a search operation in which the focusing lens group is moved along an optical axis from one of the infinite focus position (far extremity/position for bringing an object at infinity into focus) and the closest (shortest) focus position (near extremity/position for bringing an object at the shortest distance in working range into focus) to the other. A digital camera having this type of focus adjusting system drives the focusing lens group to the in-focus position, and thereupon enters a ready-to-photograph state after having performed the aforementioned search operation from the closest focus position to the infinite focus position upon the release button being depressed by half a step (refer to Japanese Laid-Open Patent Publication (Kokai) 2000-258681).
It is sometimes the case that the photographer fully depresses the release button of a camera followed by a half-step depression of the release button because the photographer does not want to risk missing even the slightest chance of a photographic opportunity. However, in conventional digital cameras, even if the release button is fully depressed in a single stroke, the shutter is not released until the focusing lens group is moved to an in-focus position after completion of the search operation from the closest focus position to the infinite focus position.